Wood chipper



y 0, 1966 J. R. DUNBAR 3,250,305

WOOD GHIPPER Filed Jan. 31, 1964 4 Sheets-Sheet 1 INVENTOR. Wm! 2x84? zzr5 Attorne y y 0. 1966 .J. R. DUNBAR 3,250,305

WOOD CHIPPER Filed Jan. 31, 1964 4 Sheets-Sheet 2 INVENTOR. $4M: 241m YAttorne y May 10, 1966 Filed Jan. 51, 1964 J. R. DUNBAR 3,250,305

WOOD CHIPPER 4 Sheets-Sheet 3 ZNVENTOR Marts 210344 Attorney J. R.DUNBAR WOOD CHIPPER May 10,, 1966 4 Sheets-Sheet 4.

Filed Jan. 31, 1964 FIG. 8

FIG. 7

INVENTOR. 5 405: 24/144 BY Attorney FIG. 9

United States Patent 3,250,305 WOOD CHIPPER James Robert Dunbar, NorthDelta, British Columbia, Canada, assignor to Cargate WestminsterIndustries Limited, New Westminster, British Columbia, Canada Filed Jan,31, 1964, Ser. No. 341,511 18 Claims. (Cl. 144172) This inventionrelates to a wood chipper. More particularly, this invention relates toa Wood chipper for cutting logs and other wood pieces into chips forsuch uses as the manufacture of wood pulp for paper-making and otherapplications.

Prior art types of wood chippers suifer from a number of inherentdisadvantages. chippers produce oversized chips, sawdust and finesduring operation because of their inability to make a clean cut, andthese undesirable materials subsequently must be screened out. Thus, onthe one hand, some wood chipper-s fail to out completely through thewood pieces, and parts of the wood pieces are broken or torn off,resulting in the production of sawdust and slivers. Furthermore, thebreaking or tearing effect so produced increases the horsepower requiredto operate these wood chippers beyond that which should be necessary. Onthe other hand, many wood chippers produce a crushing rather than ashearing action resulting in the production of oversized chips, sawdustand fines and increasing the horsepower requirements of such woodchippers beyond that which would be required if a clean out were made.

Many Wood chippers are unable to produce wood chips of consistentlength, and in the production of wood chips to be made into paper-makingpulp, it is important that wood chips of relatively consistent length beprovided.

Still other wood chippers smear or close the end pores of one or bothends of the wood chips after they have been cut, thereby effectivelyclosing the ends of the wood chips, so as to make it difficult fordigesting acids to penetrate the chips.

Many wood chippers are not self-feeding, i.e., auxiliary feedingapparatus for feeding the wood pieces to such For example, some woodwood chippers must be employed. This adds to the cost and complexity ofthe overall apparatus.

An important object of this invention is to provide a wood chipper whichmakes an extremely clean cut and which produces a minimum of oversizedchips, sawdust, slivers and fines.

Another object of this invention is to provide a wood chipper that isself-feeding.

A further object of this invention is to provide a wood chipper designedso that the cut end of the chip is not wiped, sealed or smeared by theaction of the chipper.

Yet another object of this invention is to provide a wood chipper whichis capable of producing wood chips of consistent length, and yet whichis such that adjustments may be made in the length of the chips cut atany one time.

In accordance with this invention there is provided a wood chippercomprising a knife-supporting member and means for rotatably supportingthe knife-supporting member. The knife-supporting member has first andsecond side walls which are inclined towards each other so that the sidewalls define in the knife-supporting member a peripheral groove ofgenerally V-shaped configuration lying in the plane of rotation of theknife-supporting member. At least first and second knives, each having acutting edge, are supported by the knife-supporting membet, and meansare provided for rotating'this member 3,250,305 Patented May 10, 1966and the first and second knives in a first direction. The two kniveseach have parts thereof including the cutting edges which project beyondthe first and second side Walls respectively into the generally V-shapedgroove. These parts of the knives are inclined at an obtuse angle to theportions of the first and second side walls adjacent these parts withthe cutting edges of the knives leading the knives in the direction ofrotation thereof. The first and second knives are positioned opposite toeach other. The cutting edges of the knives each have a leading portionwhich is positioned remote from the bottom of the generally V-shapedgroove and a trailing portion which is positioned nearer to the 'bottomthan the leading portion. The cutting edges are inclined in thedirection of rotation from their trailing portions to their leadingportions so that the leading portions lead the trailing portions. Theknife-supporting member has openings therein adjacent the cutting edgeswhich permit the passage of wood chips cut by the knives through theknife-supporting member. A wood-supporting member is provided forsupporting wood to be cut into chips by the knives. The wood-supportingmember has a trough therein which is adapted to receive wood to be cutand has a generally V-shaped end which projects and generally pointsinto the aforementioned V-shaped groove. The V-shaped end includes twoedges which are inclined towards each other towards the bottom of thetrough and also which are inclined at an acute angle to the bottom ofthe trough. The woodsupporting member is positioned such that the knivespass closely adjacent to the edges of the woodsupporting memher duringrotation of the knives past these edges, and also such that woodsupported in the trough is compressed between the first and secondknives and the wood supporting member during cutting of the wood byrotation of the knives.

This invention will become more apparent from the following detaileddescription, taken in conjunction with the appended drawings, in which:1

FIGURE 1 is a perspective view of a wood chipper embodying thisinvention with the hood thereof removed;

FIGURE 2 is a section through the centre of the knifesupporting memberof the wood chipper shown in FIG- URE 1, the section being taken in theplane of rotation of the knife-supporting member;

FIGURE 3 is a top elevation of a part of the wood chipper illustrated inFIGURE 1;

FIGURE 4 is a section similar to FIGURE 2 but schematic in nature;

FIGURES 5 and 6 are schematic top and front eleva tions respectively ofthe knife-supporting member of a wood chipper embodying this invention;

FIGURES 7 and 8 are front and side elevations respectively of awood-supporting member which may be used with a wood chipper embodyingthis invention; and

FIGURE 9 is a side elevation showing how the woodsupporting member ofFIGURES 7 and 8 may be mounted for rotation about the axis of rotationof the knife-supporting member.

Referring to the drawings, and, in particular, to FIG- URES 1-3, a woodchipper 10 embodying this invention includes a knife-supporting member11 composed of left and right-hand parts 11a and 11b. Each part 11a and11b has an integral hub 12. A shaft 13 passes through openings in hubs12, and any suitable means (not shown) are employed to fix hubs 12, andhence parts 11a and 11b, to shaft 13, these means not only serving toprevent v 3 parts 11a and 11b from rotating on shaft 13, but also beingeifective to hold parts 11a and 11b together with the smooth planarfaces 14 thereof in abutment with each other. Knife-supporting member 11could be formed in one piece if desired.

Knife-supporting member 11 is rotatably supported in bearings 15 and 16with shaft 13 being journalled in these bearings. Bearings 15 and 16 arefastened to rigid frame members 21 and 22 fixed in position relative toeach other.

Any suitable prime mover such as an electric motor 17 is provided torotate knife-supporting member 11 in the direction shown by the arrow inFIGURE 1, motor 17 having its drive shaft (not shown) coupled to apulley 18 which drives a pulley 19 through belts 20. It will beunderstood, of course, that pulley 19 is secured to shaft 13 by anysuitable means (not shown). It will be seen from FIGURE 1 thatknife-supporting member 11 rotates about a horizontal axis of rotation,or, in other words, that the longitudinal axis of shaft 13 ishorizontal, but it should be appreciated that shaft 13 may be placed indifferent attitudes if desired. I

Knife-supporting member 11 has side walls 23 and 24 which are inclinedtowards each other. These side walls define in knife-supporting member11 a peripheral groove 25 which is of V-shaped configuration and whichlies in the plane of rotation of knife-supporting member 11, i.e.,perpendicular to the axis of rotation thereof.

Knife-supporting member 11 is provided with slots or pockets 26 in whichare positioned non-radial knives 27 and 28. Knives 27 and 28 are heldfirmly in pockets 26 by fastening members 60.

Parts 27a and 28a of knives'27 and 28 respectively, which parts includethe cutting edges 27b and 28b of knives 27 and 28 respectively, projectbeyond side walls 23 and 24 respectively into V-shaped groove 25. Parts27a and 28a are inclined at an obtuse angle to the portions of therespective side walls 23 and 24 which are ad jacent and behind theseparts in the direction of rotation of knife-supporting member 11.Cutting edges 27b and 28b lead knives 27 and 28 respectively in thedirection of rotation of knife-supporting member 11.

Cutting edges 27b and 28b each have a leading portion 29 remote from thebottom of groove 25 and a trailing portion 30 adjacent-the bottom ofgroove 25. The knives are abuttedadjacent the bottom of groove 25 attheir trailing portion 30. Cutting edges 27b and 28b are inclinedtowards rather than against the direction of rotation ofknife-supporting member 11 from their trailing portions to their leadingportions, so that the leading portions lead the trailing portions. Thisis best shown in FIG- URES 4 and 6. Referring to FIGURE 6, when cuttingedges 27b and 28b are viewed such that they are bisected by a planepassing through the axis of rotation of knifesupporting member 11, theplane angle 31 between the cutting edges, i.e., the angle betweencutting edges 27b and 28b when projected onto a plane perpendicular tothe aforementioned plane and at right angles to the direction ofviewing, in other words, in the case of FIGURE 6, the angle 31 in theplane of the paper, is less than 180, and leading portions 29 arepositioned ahead of trailing portions 30 in the direction of rotation ofknife-supporting member 11. Similarly, in FIGURE 4 when either cuttingedge is viewed such that it is bisected by a plane passing through theaxis of rotation of knife-supporting member 11, the plane angle 32between the cutting edge and this plane, i.e., the angle between thecutting edge and this plane when projected onto a plane at right anglesto the aforementioned plane and perpendicular to the direction ofviewing, in other words, in the case of FIGURE 4, the angle 32 in theplane ofthe paper, is an acute angle, and leading portions 29 arepositioned ahead of trailing portions 30 in the direction of rotation ofknife-supporting member 11.

Knives 27 and 28 are positioned opposite each other and aresymmetrically located on either side of the plane of rotation ofknife-supporting member 11 passing through the bottom of groove 25.

In the embodiment of the invention illustrated two sets of knives 27 and28 spaced 180 apart are provided (see FIGURES 2 and 3). One set ofknives or more than two sets of knives, preferably equally spaced apart,can be employed however.

Knife-supporting member 11 has openings 33 therein positioned beneathblades 27 and 28. These openings permit the passage of wood chipsthrough knife-supporting member 11. The wood chips tumble out the openends 34 of knife-supporting member 11 and fall into any suitablecollecting or conveying device (not shown). Since knife-supportingmember 11 is rotating at a high speed, a cover or hood with a hingeddoor 101 (FIG- URE 9) should be provided over the apparatus to protectthe operator and to deflect wood chips which spin out of open ends 34towards the cover.

While knives.27 and 28 are held firmly in' position in knife-supportingmember 11 by fastening members 60, these members may be loosened topermit adjustments to be made in the extent that cutting edges 27b and28b project into groove 25, which permits the length of the chips cut bythe apparatus to be varied. It is desirable, however, that cutting edges2% and 285 be kept a uniform distance from side walls 23 and 24respectively throughout the lengths of the cutting edges.

It will be noted from the foregoing description that both theknife-supporting member and the sets of knives 27 and 28 are symmetricalabout the plane of rotation of knife-supporting member 11 through thebottom of groove 25.

While the angle 35 (FIGURE 5) between side walls 23 and 24 is notcritical, it must be less than of course. The more closely this angleapproaches 180, the less clean is the cut which is produced for a givenwood species having the same wood characteristics. Furthermore, anglesclose to 180 could cause the production of undesirable oversized chips,sawdust and slivers, particularly with eastern North American woods. Inaddition, because of the nature of the cut made under suchcircumstances, greater power is required to drive the wood chipper.Experience has shown that an angle 35 of 90 is most suitable.

While plane angles 32 and 31 are not critical, plane angle 31 must beless than 180 so as to insure that leading portions 29 actually leadtrailing portions 30 for reasons which will become more apparenthereinafter.

Experience has shown that a plane angle 31 of 152 is suitable, and thisnecessarily requires a plane angle 32 As shown in FIGURES l-3, awood-supporting member 36 is provided. Wood-supporting member 36comprises a trough 38 in which a log 39 to be cut into chips issupported. Trough 38 has side Walls 40 and 41 which are inclined towardseach other towards the bottom 46 of the trough, the bottom of the troughpreferably being rounded. Trough 38 has a V-shaped end 42 which projectsand points into groove 25 and terminates therein at a point 43. End 42comprises two edges 44 and 45 which are inclined towards each other at'avariable angle towards bottom 46 of trough 38, and which are inclined ata variable acute angle to bottom 46. Edges 44 and 45 preferablyconstitute sharp knife edges or bedknives.

It will be seen from the drawings that bottom 46 of trough 38 ishorizontal. This is not essential, but is, of course, a requirement fora horizontal feed. In the event that it is desirable to feed logs intothe chipper at an angle up to 90 from the horizontal, so that the weightof the log is used to assist in the feed thereof, or for any otherreason, wood-supporting member 36 may be mounted in such a manner thatit may be rotated around the axis of rotation of knife-supporting member11 and fixed at any angle between the horizontal and the vertical.

Thus, as shown in FIGURE 9, wood-supporting member 36 may be fixed to acrossbar 102 which is fixed to hood 100. Hood 100 has tracks 103 whichare circular and which ride in supports 104. The centre of curvature oftracks 103 is the axis of rotation of shaft 13. By loosening fasteningdevices 105 in supports 104 tracks 103 are released so that hood 100 andwood-supporting member 36 may be rotated about shaft 13. When thedesired orientation of wood-supporting member 36 is reached, fasteningdevices 105 are again secured.

As shown in FIGURE 9, door 101 is hinged at 106 and has a hooded port107 therein into which wood pieces 39 may be fed in alignment withtrough 38, it being understood, of course, that a part of the front faceof cover 100 in alignment with and below port 107 also is open.

It is desirable that the bottom of log 39 at the end thereof to bechipped be maintained above the lowermost point that is reached by thepoint of intersection of trailing portions during a complete rotation ofthe knives 27 and 28. This is ensured in the apparatus shown by makingpoint 43 higher than the lowest elevation of the bottom of groove 25which is at point 49 (FIGURE 2). It also is desirable that log 39 not beso great in diameter as to extend appreciably above the axis of rotationof knife-supporting member 11 when log 39 is horizontal.

The variable plane angle between edges 44 and 45 seen when looking atright angles to a plane passing through these edges, and the variableplane angle between either edge 44 or 45 and bottom 46 projected intothe plane of rotation of knife-supporting member 11 and viewedperpendicular to this plane, are determined by such factors as (a) theplacement of trough 38 relative to knife-supporting member 11, (b) themagnitude of angle and plane angle 31, (c) the diameter ofknifesupporting member 11, (d) the angle between sides and 41, and (e)the requirement that cutting edges 27b and 28b should pass closelyadjacent to edges and 44 respectively during rotation of the knives pastthese edges 44 and 45 to provide a scissors-like shearing action. Inconnection with requirement (c), it will be noted that the cuts or facesmade by the knives are not planar and are dished slightly inwardly.Because of the nature of the contour of the cutting path described bycutting edges 27b and 28b, in order to maintain a constant clearancebetween edges 44 and 45 and their cooperating cutting edges 28b and 2712respectively during the movement of knives 27 and 28 past edges45 and44, edges 44 and 45 preferably should not be straight. Thus, as shown inFIGURE 3, edges 44 and 45 are dished inwardly towards each other, and,as shown in FIGURES 2 and 8, also are dished in a curve which opens awayfrom the trough. While edges 44 and 45 could be made straight, it willbe appreciated that by doing so the clearance between cutting edges 27band 28b andedges 45 and 44 respectively will not remain constant asknives 27 and 28 travel past edges 45 and 44. I It is preferred thatsides 40 and 41 be at approximately to each other, and that bottom 46 oftrough 38 be radiused to correspond in curvature to the smallest loglikely to be processed, but these requirements are not critical. Anangle between sides 40 and 41. substantially greater than 120 tends tominimize the self-centering action. of the trough on a log 39, whileangles substantially less than 120 tend to result in the lifting of logsof large diameter higher than is desirable with consequent in trough 38with the fiat end of the log butted against side walls 23 and 24. Knives27 and 28 descend upon log 39 and initially engage the same at a pointbelow the axis of rotation of the knife-supporting member.

Cutting edges 27b and 28b simultaneously make initial contact with log39 in such a manner that each knife attacks the log at an angle to thegrain thereof of less than 45 As the cuttting edges cut through the log,this angle progressively decreases until, at the cut-off point, knives27 and 28 are moving in a direction substantially parallel to the woodgrain. Under these conditions, the vertically acting knife pressuresrequired when the log is initially engaged by the knives areaccommodated by the full depth of the log, which acts as an anvil at thebeginning of the cutting action. As the depth of the portion of the logwhich is uncut decreases, vertical knife pressures give Way tohorizontal knife pressures. The nearly horizontally acting knifepressures towards the end of the'cut ensure that the bottom fibres ofthe log are sliced off cleanly in the absence of vertical pressures, andthat the log is drawn towards knife-supporting member 11 in aself-feeding action. During cutting, log 39 is prevented from rolling orturning by virtue of the fact that it is in trough 38, and on account ofplane angle 31 being less than 180, which causes knives 27 and 28 tocreate a wedging effect with respect to log 39.

After the cut has been completed, the log 39 will have moved forward tothe position shown in FIGURE 1. In this position, where the sharp,freshly cut edge of the end of the log abuts the bottom of groove 25, itis important to note that faces 50 are not wiped by side Walls 23 and24, so that sealing of the faces 50 after cutting is avoided. It is alsoimportant to note that, since trailing portions 30 abut each other, thewhole end of log 39 is cut and there is no breaking or tearing action.

Since after each cut log 39 has been pulled forwardly in trough 38 tothe same extent, chips of consistent length are cut. These chips passthrough openings 33, out open. ends 34 and are collected asaforementioned.

While preferred embodiments of this invention have been describedherein, those skilled in the art will appreciate that changes andmodifications may be made therein without departing from the spirit andscope of this invention as defined in the appended claims.

What I claim as my invention is:

1. A wood chipper comprising a knife-supporting member, means forrotatably supporting said knife-supporting member, said knife-supportingmember having first and second side walls inclined towards each other,said side Walls defining in said knife-supporting member a peripheralgroove of generally V-shaped configuration lying in the plane ofrotation of said knife-supporting member, at least first and secondknives each having a cutting edge and each being supported by saidknife-supporting member, means for rotating said knife-supporting memberand said first and second knives in a first direction, said first knifehaving a part thereof including said cutting edge of said first knifeprojecting beyond said first side wall into said generally V-shapedgroove, said part of said first knife being inclined at an obtuse angleto a portion of said first side wall adjacent said part of said firstknife with said cutting edge of said first knife leading said firstknife in said first direction of rotation of said first knife, saidsecond knife having a part thereof including said cutting edge of saidsecond knife projecting beyond said second side Wall into said'generally V-shaped groove, said part of said second knife being inclinedat an obtuse angle to a portion of said second side wall adjacent saidpart of said second knife with said cutting edge of said second knifeleading said second knife in said first direction of rotation of saidsecond knife, said first and second knives being positioned opposite toeach other, said cutting edges of said knives each having a leadingportion positioned remote from the bottom of said generally V-shapedgroove and .a trailing portion positioned nearer to said bottom thansaid leading portion, said cutting edges being inclined in said firstdirection .of rotation from said trailing portions to said leadingportions, whereby said leading portions lead said trailing portions,said knife-supporting member having openings therein adjacent saidcutting edges and adapted to permit passage of wood chips cut by said'knives through said knife-supporting member, and a Wood-supportingmember for supporting wood to be cut into chips by said knives, saidwood-supporting member having a trough therein adapted to receive woodto be cut, said wood-supporting member having a generally V- shaped endprojecting and generally pointing into said generally V-shaped groove'insaid knife-supporting member, said generally V-shaped end including twoedges inclined towards each other towards the bottom of said trough andinclined at an acute angle to said bottom of said trough, said edges ofsaid wood-supporting member being positioned with respect to saidfirst'and second knives such that said first and second knives passclosely adjacent to said edges of said Wood-supporting member duringrotation of said first and second knives in said first direction andpast said edges of said wood-supporting member, said wood-supportingmember being positioned such that wood supported thereby is compressedbetween said first and second knives and said wood-supporting memberduring cutting of said wood by rotation of said knives in said firstdirection.

2. A wood chipper according to claim 1 wherein said first and secondknives are symmetrically positioned about a plane passing through saidbottom of said generally V-shaped groove.

3. A wood chipper according to claim 2 wherein said knife-supportingmember is symmetrical about said plane passing through said bottom ofsaid generally V-shaped groove.

4. A wood chipper according to claim 1 wherein at least said cuttingedges of said knives abut against each other adjacent said bottom ofsaid generally V-shaped groove.

5. A wood chipper according to claim 1 wherein said cutting edges ofsaid first and second knives each project a constant distance beyondsaid first andsecond side gills respectively throughout the lengths ofsaid cutting e ges.

6. A wood chipper according to claim 1 wherein said edges of saidwood-supporting member are knife edges.

7. A 'wood chipper according to claim 1 including means for adjustingthe position of said first and second knives with respect to saidknife-supporting member.

8. A wood chipper according to claim 1 wherein the included anglebetween said first and second side walls,

is substantially 90.

9. A wood chipper according to claim 1 wherein the plane angle betweensaid cutting edges is substantially 152.

10. A wood chipper according to claim 1 wherein said edges of saidwood-supporting member are dished in- Wardly towards each other and alsoare curved in curves opening away from said trough.

11. A wood chipper according to claim 1 including means supporting saidwood-supporting member for rotation about said knife-supporting member.

12. A wood chipper according to claim 3 wherein at least said cuttingedges of said knives abut against each other adjacent saidv bottom ofsaid'generally V-shaped groove, wherein said cutting edges of said firstand second knives-each project a constant distance beyond said first andsecond side walls respectively throughout the lengths of said cuttingedges, and wherein said edges of said woodsupporting member are knifeedges.

13. A wood chipper according to claim 12 wherein the included anglebetween said first and second side walls is substantially 90, andwherein the plane angle between said cutting edges is substantially 152.

14. A wood chipper comprising a knife-supporting member, means forrotatably supporting said knifesupporting member about a horizontal axisof rotation, said knife-supporting member having first. and second sidehaving a part thereof including said cutting edge of said first knifeprojecting beyond said first side wall into said generally V-shapedgroove, said part of said first knife being inclined at an obtuse angleto a portion of said first side wall adjacent said part of said firstknife with said cutting edge of said first knife leading said firstknife in said first direction of rotation of said first knife, saidsecond knife having a part thereof including said cutting edge of saidsecond knife projecting beyond said second side wall into said generallyV-shaped groove, said part of said second knife being inclined at anobtuse angle to a portion of said second side wall adjacent said part ofsaid second knife with said cutting edge of said second knife leadingsaid second knife in said first direction of rotation of said secondknife, said first and second knives being positioned opposite to eachother, said cutting edges of said knives each having a leading portionpositioned remote from the bot-tom of said generally V-shaped groove anda trailing portion positioned nearer to said bottom than said leadingportion, said cutting edges being inclined in said first direction ofrotation from said trailing portions to said leading portions, wherebysaid leading portions lead said trailing portions, said knife-supportingmember having openings therein adjacent said cutting edges and adaptedto permit passage of wood chips cut by said knives through saidknife-supporting member, and a wood-supporting member for supportingWood to be cut into chips by said knives, said wood-supporting memberhaving a trough therein adapted to receive wood to be out, saidwood-supporting member having a generally V- shaped end projecting andgenerally pointing into said generally V-shaped groove in saidknife-supporting member and terminating within said generally V-shapedgroove at a terminus below said horizontal axis of rotation of saidknife-supporting member, at least the part of the bottom of said troughat said generally V-shaped end thereof being positioned above the lowestelevation of 'edges of said wood-supporting member, said Woodsupportingmember being positioned such that wood supported thereby is compressedbetween said first and second knives and said wood-supporting memberduring cutting of said wood by rotation of said knives in said firstdirection.

15. A wood chipper according to claim 14 wherein said bottom of saidtrough is horizontal.

16. A wood chipper according to claim 14 wherein said first and secondknives are symmetrically positioned 17. A wood chipper according toclaim 16 wherein at least said cutting edges of said knives abut againsteach other adjacent said bottom of said generally V-shaped.

groove, wherein said cutting edges of said first .and second knives eachproject a constant distance beyond said;

9 10 first and second side walls respectively throughout the ReferencesCited by the Examiner iii-353155 535135555 @2333 fi si edges of UNITEDSTATES PATENTS 18. A Wood chippier according to claim 17 wherein said777,779 12/1904 Dmbenner 241 91 edges of said wood-supporting member aredished in- 5 825,925 7/1906 Moravec 144-172 X wardly towards each otherand also are curved in curves 3190326 6/1965 Standal 144-162 openingaway from said trough, and including means supporting saidwood-supporting member for rotation about WILLIAM DYER Primary Exammersaid knife-supporting member. W. D. BRAY, Assistant Examiner.

1. A WOOD CHIPPER COMPRISING A KNIFE-SUPPORTING MEMBER, MEANS FORROTATABLY SUPPORTING SAID KNIFE-SUPPORTING MEMBER, SAID KNIFE-SUPPORTINGMEMBER HAVING FIRST AND SECOND SIDE WALLS INCLINED TOWARDS EACH OTHER,SAID SIDE WALLS DEFINING IN SAID KNIFE-SUPPORTING MEMBER A PERIPHERALGROOVE OF GENERALLY V-SHAPED CONFIGURATION LYING IN THE PLANE OFROTATION OF SAID KNIFE-SUPPORTING MEMBER, AT LEAST FIRST AND SECONDKNIVES EACH HAVING A CUTTING EDGE AND EACH BEING SUPPORTED BY SAIDKNIFE-SUPPORTING MEMBER, MEANS FOR ROTATING SAID KNIFE-SUPPORTING MEMBERAND SAID FIRST AND SECOND KNIVES IN A FIRST DIRECTION, SAID FIRST KNIFEHAVING A PART THEREOF INCLUDING SAID CUTTING EDGE OF SAID FIRST KNIFEPORJECTING BEYOND SAID FIRST SIDE WALL INTO SAID GENERALLY V-SHAPEDGROOVE, SAID PART OF SAID FIRST KNIFE BEING INCLINED AT AN OBTUSE ANGLETO A PORTION OF SAID FIRST SIDE WALL ADJACENT SAID PART OF SAID FIRSTKNIFE WITH SAID CUTTING EDGE OF SAID FIRST KNIFE LEADING SAID FIRSTKNIFE IN SAID FIRST DIRECTION OF ROTATION FOR SAID FIRST KNIFE, SAIDSECOND KNIFE HAVING A PART THEREOF INCLUDING SAID CUTTING EDGE OF SAIDSECOND KNIFE PROJECTING BEYOND SAID SECOND SIDE WALL INTO SAID GENERALLYV-SHAPED GROOVE, SAID PART OF SAID SECOND KNIFE BEING INCLINED AT ANOBTUSE ANGLE TO A PORTION OF SAID SECOND SIDE WALL ADJACENT SAID PART OFSAID SECOND KNIFE WITH SAID CUTTING EDGE OF SAID SECOND KNIFE LEADINGSAID SECOND KNIFE IN SAID FIRST DIRECTION OF ROTATION OF SAID SECONDKNIFE, SAID FIRST AND SECOND KNIVES BEING POSITIONED OPPOSITE TO EACHOTHER, SAID CUTTING EDGES OF SAID KNIVES EACH HAVING A LEADING PORTIONPOSITIONED REMOTE FROM THE BOTTOM OF SAID GENERALLY V-SHAPED GROOVE ANDA TRAILING PORTION POSITIONED NEARER TO SAID BOTTOM THAN SAID LEADINGPOSITION, SAID CUTTING EDGES BEING INCLINED IN SAID FIRST DIRECTION OFROTATION FROM SAID TRAILING PORTIONS TO SAID LEADING PORTIONS, WHEREBYSAID LEADING PORTIONS LEAD SAID TRAILING PORTIONS, SAID KNIFE-SUPPORTINGMEMBER HAVING OPENINGS THEREIN ADJACENT SAID CUTTING EDGES AND ADAPTEDTO PERMIT PASSAGE OF WOOD CHIPS CUT BY SAID KNIVES THROUGH SAIDKNIFE-SUPPORTING MEMBER, AND A WOOD-SUPPORTING MEMBER FOR SUPPORTINGWOOD TO BE CUT INTO CHIPS BY SAID KNIVES, SAID WOOD-SUPPORTING MEMBERHAVING A TROUGH THEREIN ADAPTED TO RECEIVE WOOD TO BE CUT, SAIDWOOD-SUPPORTING MEMBER HAVING A GENERALLY VSHAPED END PROJECTING ANDGENERALLY POINTING INTO SAID GENERALLY V-SHAPED GROOVE IN SAIDKNIFE-SUPPORTING MEMBER, SAID GENERALLY V-SHAPED END INCLUDING TWO EDGESINCLINED TOWARDS EACH OTHER TOWARDS THE BOTTOM OF SAID TROUGH ANDINCLINED AT AN ACUTE ANGLE TO SAID BOTTOM OF SAID TROUGH, SAID EDGES OFSAID WOOD-SUPPORTING MEMBER BEING POSITIONED WITH RESPECT TO SAID FIRSTAND SECOND KNIVES SUCH THAT SAID FIRST AND SECOND KNIVES PASS CLOSELYADJACENT TO SAID EDGES OF SAID WOOD-SUPPORTING MEMBER DURING ROTATION OFSAID FIRST AND SECOND KNIVES IN SAID FIRST DIRECTION AND PAST SAID EDGESOF SAID WOOD-SUPPORTING MEMBER, SAID WOOD-SUPPORTING MEMBER BEINGPOSITIONED SUCH THAT WOOD SUPPORTED THEREBY IS COMPRESSED BETWEEN SAIDFIRST AND SECOND KNIVES AND SAID WOOD-SUPPORTING MEMBER DURING CUTTINGOF SAID WOOD BY ROTATION OF SAID KNIVES IN SAID FIRST DIRECTION.